Process for preparing salts of alkyl and alkenylguanidines

ABSTRACT

When monoalkylamines, dialkylamines, monoalkenylamines, or dialkenylamines having 11 to 18 carbon atoms in the hydrocarbon chain or chains are reacted in equimolecular amounts with lower alkanoic acids and cyanamide in the absence of solvents and at a temperature high enough to keep the mixture molten, but not much higher than 170*C., the expected substituted guanidine salts are formed quickly in yields of 90 percent or better. Impurities, such as iron ions, do not interfere and no pH adjustment is needed.

v 'UIHtGd States Patent 1 [111 3,723,51 1 Prietzel A Mar. 27, 1973PROCESS FOR PREPARING SALTS OF Primary ExaminerI -,eon Zitver ALKYL ANDALKENYLGUANIDINES Assistant Examiner-Gerald A. Schwartz [75] Inventor:Horst Prietzel, Trostberg, Germany Attorney Kehnan and Batman [73]Assignee: Suddeuts'c he Kalksticksloff-Werke [57] ABSTRACT TrostbetgGermany When monoalkylamines, dialkylamines, monoal- Filedi July 1970kenylamines, or dialkenylarnines having 11 to 18 car- [21] Appl. 52,113bon atoms in the hydrocarbon chain or chains are reacted inequimolecular amounts with lower alkano1c v acids and cyanamide in theabsence of solvents and at [52] Cl. ..260/501.l4 a temperaturehighenough to keep the mixture [51] Int. Cl ..C07c 129/00 ten, b not hhigher than 170 the expected [58] Fleld of Search ..260/501.14, 564 ASubstituted guanidine Salts are formed i k in yields of 90 percent orbetter. Impurities, such as iron ions, 5 References cued do notinterfere and no pH adjustment is needed.

' UNITED STATES PATENTS 6 Claims, No Drawings 3,383,408 5 /1968 Lies..260/50l.l4 v

PROCESS FOR PREPARING SALTS OF ALKYL AND ALKENYLGUANIDINES The presentinvention relates to a process for preparing alkyland alkenyl-guanidineslats from alkylamines, aliphatic carboxylic acids, and cyanamide.

In U. S. Pat. specification No. 3,004,065, there is described a processfor preparing alkyl-guanidine salts in aqueous solution from alkylaminescontaining more than carbon atoms in the alkyl radical, salts of theseamines, cyanamide and the acids which provide the anionic moiety of theamine slats. The reaction conditions include a temperature of 95 to 100C. and a pH value of at least 9. In this process, it is important forachieving an acceptable yield that the cyanamide solution used be freeof ferric ions. Even so, there is achieved a maximum yield of only 80percent, based on the amount of amine used, or of 52 percent, based on.the amount of cyanamide used, there being employed a considerable excessof cyanamide, as well as an excess of acid over the amine used. Aparticular disadvantage of this known process is the long period ofreaction, typically 3.5 hours.

Furthermore, from U. S. Pat. specification No. 3,383,408, there is knowna process for preparing alkyl-guanidine salts from alkylamines,carboxylic acids, and an aqueous cyanamide solution in which thestarting materials are reacted in substantially equimolar amounts at atemperature of about 70- 150 C. The period of reaction in this processis as much as 5 hours and the obtained yields of 31.5 73 percent arealso unsatisfactory.

The object of the present invention is an economical,

Thereaction temperature and optimum reaction tion mixture must be moltenat the chosen temperature.

The starting materials are used in equimolecular amounts. The yieldswhich can be achieved by means of the process according to the presentinvention are between 90 and 96 percent, based on the amounts of amineor cyanamide employed as starting materials. Surprisingly, we have foundthat the yield is generally reduced by the amount by which the reactantsexceed the molar ratio. Thus, if an excess of cyanamide or of acid isused, the degree of conversion of the amine is decreased and notincreased.

if desired, the process according to the present invention can becarried out continuously, for example, in a flow-through tube.

It is a particular advantage of the process according to the presentinvention that the pH value of the melt and the purity of the startingmaterials are not critical. Thus, ferric ions present in the cyanamidedo not exert an undesirable influence on the course of the reaction.

simple process of preparing alkylor alkenyl-guanidine salts from thecorresponding amines, aliphatic carboxylic acids, and cyanamide, whichprocess overcomes the above-mentioned disadvantages of the knownprocesses.

According to the present invention, alkyland alkenyl-guanidine salts areprepared from alkylamines or alkenyl-amines containing more than 10carbon atoms in a hydrocarbon radical, aliphatic carboxylic acids, whichpreferably contain up to '5 carbon atoms, and cyanamide in substantiallyequimolecular amounts at a temperature of 80- 170 C., preferably of 100-150 C., without the use of a solvent, in a melt within a period of 3minutes.

The cyanamide may be used as a solid or as an aqueous solution or slurrycontaining more than 50 percent cyanamide. When a cyanamide solution orslurry is used, it is necessary to prevent substantial amounts of waterfrom entering the melt. According to a preferred embodiment of theprocess according to the present invention, the cyanamide solution orslurry is added under conditions under which the water evaporatesimmediately. Solid cyanamide is added to the amine salt melt preferablybefore the melt has reached the reaction temperature so that thereaction components are well mixed when the reaction begins.

The period during which the reactants are kept at the reactiontemperature must be controlled carefully. If it is less than 3 minutes,the reaction is incomplete. When the period of heating exceeds 30minutes, a significant amount of the guanidine formed decomposes. Longerperiods of reaction are used when the cyanamide is added in the form ofa solution than with cyanamide in solid form.

Products obtained by the process according to the present invention canbe used as algicides, fungicides,

or wetting agents, as is known in itself.

The following Examples further illustrate the present invention. Allparts are by weight unless stated otherwise.

EXAMPLE 1 Into an open vessel equipped with a stirrer and a heating orcooling jacket, there were placed 50 parts dodecylamine and 16.2 partsglacial acetic acid. The dodecylamine acetate formed after mixing wasmelted at C., and 12.2 parts cyanamide percent) were introduced. Themole ratio of dodecylamine:acetic acid; cyanamide was 1:1:1. Heating wascontinued until the reaction mixture reached C. The tem-v peratureslowly increased spontaneously thereafter due to the exothermicreaction. From 130 C the reaction mixture was cooled to 1 15 C. Thetotal reaction time was 5 minutes. Thereafter, the melt, which was notvery viscous, was discharged and permitted to solidify in crystallineform. It contained 90.0 percent dodecylguanidine acetate. Thus, theyield was 90 percent, calculated on the dodecylamine or on the cyanamideused.

Example 2 Example 3 50 Parts dodecylamine were heated in a closed vesselwith 16.2 parts glacial acetic acid to C. and

1 1.8 parts cyanamide were added dropwise at this temperature over aperiod of minutes in the form of a 50 percent solution in water. Duringthe addition of the cyanamide solution, the reaction mixture was heatedto 130C. while the vacuum of a water jet pump was applied, andthereafter again cooled to 1 C. The reaction time, after the lastaddition of cyanamide, was 15 minutes. There were obtained 78.6 parts ofmelt containing 88.5 percent dodecyl-guanidine acetate, corresponding toa yield of 89.5 percent, calculated on the dodecylamine or on thecyanamide used.

Example 4 50 Parts oleylamine were melted with l 1.2 parts glacialacetic acid at 90 95C., 8.0 parts 98 percent cyanamide were introducedand the mixture was heated to 130C. After a total reaction time of 15minutes, the honey-colored melt was discharged from the reaction vesseland solidified in crystalline form. There were obtained 69.2 parts of aproduct containing 91.2 percent oleyl-guanidine acetate.

Example 5 Example 6 50 Parts oleylamine were mixed with 8.6 parts 100percent formic acid, and 8.0 parts 98 cyanamide were introduced at 90C.The reaction proceeded with slight foaming at increasing temperature. At130C., the temperature increase was broken off by cooling, and the meltwas maintained at 110 1 15C. for 12 minutes. There were obtained 66.6parts of a product having the consistency of a paste and containing 75percent oleylguanidine formate. The purity was the same as the yieldbecause the components were used in a mole ratio of 1:121.

Example 7 50 Parts oleylamine were melted with 13.9 parts propionic acid(99 percent), and 8.0 parts 98 percent cyanamide were mixed in at C. Thetemperature of the reaction mixture was brought to C. by heating,because the reaction was less vigorous than with formic or acetic acid,and subsequently maintained for 10 minutes at 115C. Upon cooling, theproduct solidified to 7.18 parts of a wax-like mass containing 91.6percent oleyl-guanidine propionate. The yield, therefore, was 91.6percent based on any one of the starting materials.

What is claimed is: v

l. A process for preparing an alkyl or alkenylguanidine salt whichcomprises reacting equimolecular amounts of a monoalkylamine,dialkylamine, monoalkenylamme or dialkenylamme having from 11 to 18carbon atoms in the hydrocarbon chain, of a lower alkanoic acid, and ofcyanamide in the absence of solvent at a temperature sufficient to keepthe reaction mixture molten but no higher than 170C until said alkyloralkenyl-guanidine salt is formed, but not longer than 30 minutes.

2. A process as set forth in claim 1, wherein said aliphatic amine andsaid alkanoic acid are combined prior to said reacting, and thecyanamide is added thereafter to the product so obtained.

3. A process as set forth in claim 2, wherein said cyanamide is added tosaid product in the form of an aqueous slurry or solution containingmore than 50 percent of said cyanamide under conditions causingsubstantially complete evaporation of the water in said slurry orsolution prior to said reacting.

4. A process as set forth in claim 2, wherein said cyanamide is added tosaid product in the solid state at a temperature lower than thetemperature required for reacting said cyanamide with said product.

5. A process as set forth in claim 1, wherein said temperature isbetween 100 and C.

6. A process as set forth in claim 1, said temperature being at least 80C.

2. A process as set forth in claim 1, wherein said aliphatic amine andsaid alkanoic acid are combined prior to said reacting, and thecyanamide is added thereafter to the product so obtained.
 3. A processas set forth in claim 2, wherein said cyanamide is added to said productin the form of an aqueous slurry or solution containing more than 50percent of said cyanamide under conditions causing substantiallycomplete evaporation of the water in said slurry or solution prior tosaid reacting.
 4. A process as set forth in claim 2, wherein saidcyanamide is added to said product in the solid state at a temperaturelower than the temperature required for reacting said cyanamide withsaid product.
 5. A process as set forth in claim 1, wherein saidtemperature is between 100* and 150* C.
 6. A process as set forth inclaim 1, said temperature being at least 80* C.